linux-kernel - [PATCH] hugetlb/cgroup: Simplify pre

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 18 Jul 2012 11:04:09 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	linux-mm@...ck.org, kamezawa.hiroyu@...fujitsu.com, mhocko@...e.cz,
	akpm@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [PATCH] hugetlb/cgroup: Simplify pre_destroy callback

From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>

Since we cannot fail in hugetlb_cgroup_move_parent, we don't really
need to check whether cgroup have any change left after that. Also skip
those hstates for which we don't have any charge in this cgroup.

Based on an earlier patch from  Wanpeng Li <liwanp@...ux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
 mm/hugetlb_cgroup.c |   49 +++++++++++++++++++++----------------------------
 1 file changed, 21 insertions(+), 28 deletions(-)

diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index b834e8d..b355fb4 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -65,18 +65,6 @@ static inline struct hugetlb_cgroup *parent_hugetlb_cgroup(struct cgroup *cg)
 	return hugetlb_cgroup_from_cgroup(cg->parent);
 }
 
-static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg)
-{
-	int idx;
-	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cg);
-
-	for (idx = 0; idx < hugetlb_max_hstate; idx++) {
-		if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0)
-			return true;
-	}
-	return false;
-}
-
 static struct cgroup_subsys_state *hugetlb_cgroup_create(struct cgroup *cgroup)
 {
 	int idx;
@@ -159,24 +147,29 @@ static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)
 {
 	struct hstate *h;
 	struct page *page;
-	int ret = 0, idx = 0;
+	int ret = 0, idx;
+	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
 
-	do {
-		if (cgroup_task_count(cgroup) ||
-		    !list_empty(&cgroup->children)) {
-			ret = -EBUSY;
-			goto out;
-		}
-		for_each_hstate(h) {
-			spin_lock(&hugetlb_lock);
-			list_for_each_entry(page, &h->hugepage_activelist, lru)
-				hugetlb_cgroup_move_parent(idx, cgroup, page);
 
-			spin_unlock(&hugetlb_lock);
-			idx++;
-		}
-		cond_resched();
-	} while (hugetlb_cgroup_have_usage(cgroup));
+	if (cgroup_task_count(cgroup) ||
+	    !list_empty(&cgroup->children)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	for_each_hstate(h) {
+		/*
+		 * if we don't have any charge, skip this hstate
+		 */
+		idx = hstate_index(h);
+		if (res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE) == 0)
+			continue;
+		spin_lock(&hugetlb_lock);
+		list_for_each_entry(page, &h->hugepage_activelist, lru)
+			hugetlb_cgroup_move_parent(idx, cgroup, page);
+		spin_unlock(&hugetlb_lock);
+		VM_BUG_ON(res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE));
+	}
 out:
 	return ret;
 }
-- 
1.7.10

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/